Front head for rock drills



R. H. WILHELM FRONT HEAD FOR ROCK DRILLS Filed May 10, 1927 NVENTOR.

/ [1292222 TTO%EY.

Patented May 7, 1929.

UNITED STATES 1,712,239 PATENT OFFICE.

RUSSELL H. WILHELM, 0F EASTON, PENNSYLVANIA, ASSIGNOR TO INGERSOLL-RAND COMPANY, OF JERSEY CITY, NEW JERSEY, A CORPORATION OF NEW JERSEY.

FRONT HEAD FOR ROCK DRILLS.

Application filed May 10, 1927. Seiial Nd 190,258.

This invention relates to rock drills, but more particularly to a front head for fluid actuated rock drills of the hammer type.

The objects of the invention are to distribute the wear of the cooperating surfaces of the front head and the working implement which it guides over a large area and to insure against impact of the specially formed portions of the working implement, such as the collar or other equivalent means, with the material on which the implement is operating.

Other objects will be in part obvious and in part pointed out hereinafter.

In the drawings illustrating a practical application of the invention,

Figure 1 is a side elevation in section of the front end portion of a concrete breaker,

Figure 2 is a similar view partly broken awa Figure 3 is a transverse sectional view taken on the line 3-3 of Figure 2 looking in the direction indicated by the arrows, and

Figure 4 is a fragmentary view in side elevation of a portion of the front head showing the manner in which a retaining means may be attached thereto.

Referring to the drawings, the invention is shown embodied in a rock drill in which only the front portion of a cylinder A is shown. The cylinder A is provided with a reciprocatory hammer piston B and is sealed at its front end by a front cylinder washer G which also serves to centralize a front head D with respect to the cylinder A. An additional function of the front cylinder washer C is to serve as a seat for an anvil block E disposed slidably in the washer C for transmitting the blows of the piston 13 to a working implement F guided by the front head D.

The working implement F may be of a well known type and in this instance has a polygonal shank G which extends into and-interlocks with a correspondingly shaped longitudinal bore H formed through the front head D.

Any suitable means may be provided on the working implement- F for cooperation with the front head to limit the distance which the shank G may extend into the front head I). Tn the present instance this means consists of a collar .l located at the juncture of the shank G and the body portion of the working implement F. This collar J is preferably of suliicicntly larger diameter than the bore H to afford a substantial area of contact between it h and a shoulder K in the bore which it abuts when the in'iplemont is pressed to its rearwardmostposition in the front head l).

a In the present instance the bore H extends only through a portion of the front head and con'imunicates at its front end with an enlarged cylindrical bore L formed'in the front end of the front head to receive the co lar d of the working implement F. Preferably the bore L is of somewhat larger diameter than the collar J to avoid contact between these elements. However, if desired, the collar J and the bore L may be formed to such proportions that they will cooperate slidably thus forming an additional guiding means for the working implement F.

As will be observed, the. bore L is of considerable depth. This enables the collar .l to

at all times occupy a position well removed from the work. This is a desirable feature in devices of this character, not only because it enables the front end of the front head to closely approach the working surface, but also because the collar, or such other means 'as may be substituted therefor and which means usually are expensive to form on the working implement, are at all times amply protected against injury.

Usually in rock drills of the type to which the present invention relates, means are provided for preventing ejection of the working implement from the front head. To accommodate such means in the present instance, the front head D is provided in its front end with a longitudinal slot 0 which opens from the front end of the front head and extends rearwardly through the wall of the front head to a point forwardly of the front end of the bore H. The slot 0 may be of uniform width throughout its length and opens at its inner side into the enlarged bore L and at its outer side in the periphery of the front head.

A practical use of the slot 0 is illustrated in the drawings in which a latch if is dis posed in the slot 9 to cooperate with the collar J of the working implement for the pinpose of retaining the working implement in the front head. However, any other suitable or well known latch or device may be substituted for that shown and it is to be under stood that the latch l? forms no part of the present invention, but is shown merely to illustrate a convenient use of the slot 0.

The latch P, briefly described, comprises a fill body portion Q, having an integral handle R which, when the latch is in its operative position lies against the side of the front head to prevent rocking of the latch out of retaining position whenever the collar J of the working implement F strikes against a stop S on the inner face of the body portion Q. In the present instance that portion of the edge of the body Q intermediate. the handle It and the stop S comprises a cam T which forms a seat for a spring pressed plunger U in the wall of the front head whereby the latch P may he held in its limiting or any interme diate positions in which the said latch P may lie. A pivot may be provided for the latch P in the form of a pin V disposed in suitable apertures \V in the latch P and the front head.

Any suitable means may be provided for securing the front head D in assembled position to the cylinder A. These means in the present instance consist of apertured lugs X, preferably disposed diametrically opposite each other at the rearward end of the front head to receive the usual spring pressed side bolts Y whereby the parts comprising the casing of the rock drill are held together.

Although the present invention is applicable to all types of rock drills, it is particularly adapted for drills of the concrete breaker type. These rock drills are used prineipally on work in the vicinity of which there is usually a mass of broken material. It is therefore desirable to protect the steel retaining means as well as the expensively formed portions of the working implement against injury due to the impact of these partsagalnst the work, as where material being drilled suddenly parts and the rock drill lunges forwardly with great force against the work. As will be readily seen, the present front head completely protects the more expensive parts ing device, other retaining means of any suitable type may readily be substituted therefor without seriously delaying the drilling oper- 'for dust or cuttings to lodge therein and hinder the free action of the retaining means or cause objectionable wear thereto as well as to the front head.

I claim:

1. A front head for rock drills having a longitudinal bore therethrough for the reception and guidance of a working implement, said front head being adapted to be attached to the cylinder of a rock drill, and a longitudinal slot in the front end of the front head for the reception of means for retaining the working implement in the front head, said slot opening from the front end of the front head, thus preventing the accumulation of foreign matter in the slot.

2. A front head for rock drills having a longitudinal bore therethrough for the reception of a working implement, the front end of said here being enlarged to receive a collar on such working implement, said front head ha ving a longitudinal slot opening from the front end of the front head for the reception of a latch to prevent ejection of the working implement from the bore and to prevent the accumulation, of foreign matter in the slot.

3. A front head for rock drills having a longitudinal bore therethrough for the reception of a working implement, the front end of said bore being enlarged to receive a collar on such working implement, said front head having a slot in its front end for the rceept ion of a latch to prevent ejection of the working implement from the bore, said slot extending from the periphery of the front head to the. bore and opening from the front end of the front head to prevent the accumulation of foreign matter in the slot.

In testimony whereof I have signed this specification.

RUSSELL H. \VILI-IELM. 

